This disclosure relates generally to optical fibers, and more particularly to fiber optic cable assemblies incorporating multi-fiber ferrules, and methods for fabricating fiber optic cable assemblies.
Optical fibers are useful in a wide variety of applications, including the telecommunications industry for voice, video, and data transmissions. In a telecommunications system that uses optical fibers, there are typically many locations where fiber optic cables that carry the optical fibers connect to equipment or other fiber optic cables. To conveniently provide these connections, fiber optic connectors (“connectors”) are often provided on the ends of fiber optic cables. The process of terminating individual optical fibers from a fiber optic cable is referred to as “connectorization.” Connectorization can be performed in a factory (resulting in a “pre-connectorized” or “pre-terminated” fiber optic cable) or in the field (e.g., using a “field-installable” connector).
Many different types of fiber optic connectors exist. In environments that require high density interconnects and/or high bandwidth, such as data centers, multi-fiber optical connectors are the most widely used. Multi-fiber optical connectors are suitable for use with multi-fiber cables and frequently utilize multi-fiber ferrules. One example of a multi-fiber optical connector is the multi-fiber push on (MPO) connector, which incorporates a mechanical transfer (MT) ferrule and is standardized according to TIA-604-5 and IEC 61754-7. These connectors can achieve a high density of optical fibers, which reduces the amount of hardware, space, and effort required to establish a large number of interconnects.
Despite the widespread use of MPO connectors in data center environments, there are still challenges and issues to address. For example, although MPO connectors may contain any even number of fibers between 4 and 24 within the same physical package, 12-fiber connectors are the most commonly used. For some applications, such as parallel optics for 40 Gigabits per second (Gps) Ethernet, only 8 active fibers are needed. Conversion modules may be used to convert the unused fibers from two or more MPO connectors into usable optical links (e.g., converting 4 unused fibers from each of two MPO connectors into 8 useable optical links), but the conversion adds costs to a network. Alternatively, cable assemblies can be built with only 8 fibers terminated by an MPO connector, but the MPO connector still resembles a 12-fiber connector, and it can be difficult to see with the naked eye whether 8 fibers or 12 fibers are present. This uncertainty in fiber count may result in network issues if a connector having 12 active fibers is inadvertently mated to a connector having only 8 active fibers.
Also, securing groups of fibers during assembly of a MPO connector can be challenging for fabrication steps such as fiber stripping, cleaving, and affixing fibers within a MT style ferrule. Traditional ribbonizing techniques have utilized adhesives to secure fibers together after a portion of a jacket of a multi-fiber cable is stripped. Such techniques, however, are cumbersome, and can be particularly challenging when it is desired to segregate multiple groups of fibers emanating from the same multi-fiber cable for insertion into a MT style ferrule. For example, it is very difficult to hold separate ribbons and insert them into microholes of MT style ferrules. But as difficult as it may be to manipulate two ribbons at the same time, it is even more difficult to manipulate four, eight, twelve or more loose (e.g., non-ribbonized) fibers at the same time.
Thus, the art continues to seek fiber optic cable assemblies and fabrication methods that address limitations associated with conventional assemblies and methods, including cable assemblies and methods that facilitate handling of optical fiber segments without requiring use of ribbonizing techniques.